Brake for electric motors.



Nd. 648,273. Patented Apr. 24, I900.

' C. A. LINDSTROM.

BRAKE FOR ELECTRIC MOTORS.

(Application filed Nov. 16. 1899.)

(No Model.)

Vita/q UNITED STATES- PATENT O IC I M ESNE ASSIGNMENTS, TO THE Hl lWI'FP-LlNDSTROM ()F SAMF PLACE.

Moron con PANY,

BRAKE Fo ELECTRIC Mo'roRs.

SPECIFICATION forming part Of Letters Patent NO. 648,273, dated April 24,1909.

Application filed November 16, 1899. Serial No. 737,226. No model-l I I T alt m/wlni/' may concern:

lic it known that}, CHARLES A. LLNDsTRO'M, a citizen of the United States, and a resident of lhicngodlook con nty, Illinois, have invent-- rd certain new and useful Improvements in Brakes for Electric Motors, of which the following is a full, clear, and exact description. The object ofmy invention is to provide a simple, cheap,and ell'ective brake for incloscd :0 electric motors, and particularly those used for electrically,-propellcd vehicles in which the bralcc-shoc arms and devices for actuating the same are so constructed thatit is impossible for dust or dirt to get inside of the :5 honsingof the motor, and the corresponding and simultaneous action of said brake-shoe arms is assured. This I accomplish by the means hereinafter fully described, and as particularly pointed out in the claims. no In the drawings, Figure l is a side view of my invention, showing the surrounding hood or housing thereof in section. Fig. 2 is a horizontal longitudinal section of one end of an v armature shaft, the improi'cd braking mechanism thereon, and the end or hood of the housing inclosing the same. Fig. 3 is a detail view showing the rccessing of the arms. Referring to the drawings, Arepresents the hood or end of the case orcovcrof an electric 0 motor. The center of this. hood is provided with a suitable hearing for the armatureshaft B, and just inside and so as to almost touch the hood this shaft is provided with a brake-pulley C-ofsnitnblc diameter, substantially as shown.

l) I) represent two corresponding brakeshoc arms, the greater part 'of the length of which describe a semicircle the diameter of the inncrcircnmierencc of which corresponds 0 to that ol. the pulley (J, to which they preferablycorl'cslnmd in width. The ends of these arms on one side of these pulleys extend outward from the semicircular part thereof at a suitable allele and We fulcrnmcd on studs or 5 pinsaa, projectinglnwnrd from the head of said hood at points located between the pulley and the (-ylimlricttlsidcsthereof. These studs or pins or a are preferably arranged so that one is aboveh-nd the other the same dis irrnce below horizontal plane striking.

through the center of the armature shaft, from thecenter of which theyarc equidistant;

. The ends I) b of the braking-arms opposite the pins a extend past each other and are each provided at their intersecting planes: with recesses c c in their adjacent side edges, which are one-half the width of the remain der of the length of said arms and are of p a length corresponding to the extent said arms lop past each other. These recesses c c are provided sons to avoid the nc'ccssityof increasing the width of the space occupied. by the braking-arms where they lap past each other, but where economy of space is not an object these recesses may be dispensed with.

Beyond the recesses'c (1 ends I) 1) curve outward and describe, preferably, corresponding arcs and then extend parallel to each other a short distance and terminate at points almost in touch with the inner circumference of the hood. While I do not consider it essential, I prefer to increase the width of ends 1) beyond recesses c 0 hack to that of the arm anywhere between said recesses and the fulcrumal points of arms D and to make the op- 7 posing surfaces of said parallel portions fiat.

I idwa between the parallel portions of ends I) b of arms D and so as to be intersected by the transverse or horizontal plane striking through the center of the armature-shaftSo and midway between pins 0 a is a short spindle E,. the axial center of which is parallel to shaft B and which is journaled in suitable bearing made in the head or end of hood A. On the end of this spindle, between the ends of the braking-arms, it is provided with an elliptical or a truncated diamond-shaped cam F, and on its'outer end, which extends beyond its bearings,it is provided with an arm G. The normal position of the cam F is such that itsmajor axis is inclined at an angle of about forty-five degrees to tl 1c perpcinlicular, and when arm G is moved sons to move the cam so that its major axis assumes a more nearly perpendicular position the ends of arms I) l) are thereby forced farther apart an d -th -"scmicircula-r portion of said arms brought .similltancously and with equal pressure into in; contact with the periphery of the or wheel.

I In order to normally kelp arms D D out of taneonsl'y force saidends apart and thereby braking contact with the brake pulley or causethe brake-arms to clamp the'pulley; a

wheel,I interpose between t1: 1 saidarmsa 'rock-shaftca rryingsaid cam, journaled in strong expansion-spring H and'retain said 83, projectingthroughthe endotthe casing; 5 springin position' by seating its ends in the --'uieansfor fo'cking said'shaft, and aspring in- 40 V concavities ordepressious made in' the ends te 'poscd-bfetw'een said anus and adapted to of bosses d 1, made integrant with said arms "force said arms apart when they arereleased ne%theirfulcrums, substantially as shown. v by the c forv the purpose and subsqmtiauy 1e arm G .for" operating the cam will be as described.

io forcedhacktowardits normal position-every 1 2. Inabrakefofelectmotors the comtime the actuating power is removed from} ,binatio'n of" the casing,- the. armature-shaft,-

7 said arm by splj ing H through'the 'medium pthe brake pulle'y thereon" within the' casing;

' of braking-arn qD D. Should this be insuf a pair of similar independent brake-shoe arms fici'ent; a coil torsion-a1 spring I may be coiled; disposed on opposite sides of said"pulleywith 515. around spindleEbetweenitsbeai iugsaud-arm. .int hejcasing and-having their free-ends over- I G and have one end secured to said spindle and lapped and then bent outwardly parallel with the other to thehood, in which it has its beareach other fora shortdist'ance, said free ends ings. Thus when the spindle'E is turned said being similarly recessed where; they intersect spring I isconstric tedland when said spindle each other,'"the otheneuds 'of said arms being ego ,is released thisspting; in its efio t to'resumc attached tot fiked; pivots-y-i thin 'the casing; 5 5

its normal-position contributes to restore the witha 'rocking camintel'posed between and spindle-audlthecam toits originalpositiongn directly-engaging both of; the Overlapping What I chain) as new is-'- f a fieeeuds' of the'ar'ms, and adaptedgtoforce I 1. In abrak'e' for electric motors the com "said ends apartand therebycause the brake? :5 hinat-ion of 'the, casing," the shaft, the brake-. far nisto clamp the pulley; a 'rock shaft carry- .pulley'thereoufwithin thecasi'nga pair of ing said "cam, journaled "in and projecting 'siuiila'rindependentbrakeshoearuisdisposed through the end of the casing,,meaus exte-;

Ton-opposite sides of, said pulley 'within the 'r io'r 'tothe casing for rocking said shaft; and- 1 d casing and having their free ends overlapped a spring adaptedj'to force said, arins apart 30 and then bent outwardly parallelwith each when they. are released bythercam, for the 1' other fozyashort distance, the other ends of "purpose and substantially as descrihed. v said arms-being attached to fixed pivots wi th- If CHARLES, AJLINDSTROM. I in theca'sing; with a' cam interposed betv veen Witneesesz' v A f a and diiectlyeugag'ing. both ofthe overla ed. EDWARD W. Ham

35 free en'fls ot theargns, and adapted to simul FRANK D. TIio nsoN i 

